How electricity cost is calculated
Electricity cost depends on power draw, runtime, device count, days used, and the rate charged for each kWh.
Electricity Cost Calculator
Calculate how much any appliance costs to run per hour, day, or month.
Appliance usage
Enter wattage, runtime, rate, and device count. Results update instantly.
Estimated monthly electricity cost
9.00
Based on 60.00 kWh per month.
Daily cost
0.30
Yearly cost
109.50
kWh per day
2.00
kWh per month
60.00
kWh per year
730.00
Cost per hour
0.1500
Total device load
1.000 kW
Rate used
0.1500 per kWh
Usage schedule summary
2.00 hours per day, 30 days per month, 1 device(s).
Copy result
Copy the cost estimate, kWh usage, rate, runtime, and device count.
Rate accuracy note
Check your electricity bill for the best rate estimate.
kWh explanation
A kWh means using 1 kilowatt of power for 1 hour.
Usage estimate
Real appliance use can vary by mode, age, efficiency, and operating cycle.
Appliance label note
Rated wattage may differ from measured wattage during real use.
Local calculation
Inputs are processed in your browser. No electricity rate API is required.
Dynamic electricity cost insights
Cost check
This is a modest appliance cost estimate. Runtime and rate are the main drivers.
Power load
The entered wattage is in a typical range for many household appliances.
Runtime impact
Daily runtime has a direct effect on monthly cost.
Electricity cost breakdown
Power converted to kW
1.000 kW
Hours used per day
2.00 hours
kWh per day
2.00 kWh
kWh per month
60.00 kWh
Electricity rate used
0.1500 per kWh
Daily cost
0.30
Monthly cost
9.00
Yearly cost
109.50
Number of devices
1
Standby kWh per day
0.000 kWh
Common appliance wattage guide
LED bulb
6 to 12 W
Low power, but many bulbs can add up
Laptop
30 to 90 W
Varies by charging, screen brightness, and workload
Desktop computer
100 to 500 W
Gaming and workstation PCs can use more
TV
50 to 200 W
Screen size and brightness affect use
Refrigerator
100 to 800 W
Cycles on and off through the day
Washing machine
400 to 1,400 W
Heating water increases use
Microwave
700 to 1,500 W
High power, usually short runtime
Space heater
1,000 to 1,500 W
High runtime can make monthly cost significant
Air conditioner
500 to 3,500 W
Depends on size, climate, and runtime
Electricity usage examples
100 W for 8 hours
0.8 kWh per day
Common for small electronics or lighting groups
500 W for 4 hours
2.0 kWh per day
Moderate appliance load
1000 W for 2 hours
2.0 kWh per day
Same energy as 500 W for 4 hours
1500 W for 1 hour
1.5 kWh per day
Typical high-power heater example
Rate comparison guide
Low electricity rate
Around 0.10 per kWh
Often lower cost areas or off-peak periods
Average electricity rate
Around 0.15 to 0.25 per kWh
Useful planning range in many regions
High electricity rate
Above 0.30 per kWh
Costs rise quickly for high-power appliances
Peak or time-of-use rate
Varies by schedule
Running appliances off peak may reduce cost where available
Energy saving ideas
Reduce runtime
Shorter daily use directly lowers kWh and cost
Shorter daily use directly lowers kWh and cost
Use efficient appliances
Lower wattage can reduce cost for the same task
Lower wattage can reduce cost for the same task
Check standby power
Always-on devices can add up over a month
Always-on devices can add up over a month
Use timers
Timers can limit accidental long runtimes
Timers can limit accidental long runtimes
Compare tariff periods
Time-of-use plans may make timing important
Time-of-use plans may make timing important
Electricity cost guide
These notes explain appliance cost estimates without repeating the calculator result.
What kWh means
A kilowatt-hour measures energy use over time. One 1000 watt appliance running for 1 hour uses 1 kWh.
Watts vs kilowatts
Watts measure power. Kilowatts are watts divided by 1000, which makes electricity billing calculations easier.
How to find your electricity rate
Look at your bill for the energy charge per kWh. Delivery fees, taxes, and fixed charges may be listed separately.
Why appliance labels may differ
An appliance label may show rated or maximum wattage, while real use changes with cycles, modes, and load.
Limitations of electricity cost calculators
Estimates may vary because of taxes, fees, time-of-use pricing, device efficiency, and real usage patterns.
Formula
kW = Watts ÷ 1000
kWh per Day = kW × Hours Used per Day × Number of Devices
Daily Cost = kWh per Day × Electricity Rate
Monthly Cost = Daily Cost × Days Used per Month
Yearly Cost = Daily Cost × 365
Variables
- Watts measure appliance power draw.
- kWh measures energy used over time.
- Electricity rate is the price per kWh.
- Device count multiplies total usage and cost.
Worked example
A 1000 watt appliance used for 2 hours per day uses 2 kWh daily. At 0.15 per kWh, that costs 0.30 per day and 9.00 over 30 days.
Assumptions
The estimate assumes constant wattage, the entered rate, and the selected number of monthly use days.
Limitations
Actual costs may vary because of local rates, taxes, fees, time-of-use pricing, device efficiency, and usage patterns.
Frequently asked questions
How do I calculate electricity cost from watts?
Convert watts to kilowatts, multiply by hours used per day, then multiply by your electricity rate per kWh.
What is a kWh?
A kWh is a kilowatt-hour. It means using 1 kilowatt of power for 1 hour.
How do I find my electricity rate?
Check your electricity bill and look for the cost per kWh. Some bills also include delivery fees, taxes, fixed charges, and time-of-use rates.
Why is my appliance cost estimate different from my bill?
Bills can include fixed charges, taxes, delivery fees, peak pricing, and other appliances. This calculator estimates one appliance or device group.
Do appliances always use their rated wattage?
No. Rated wattage is often a maximum or typical value. Real use can vary by mode, temperature, load, cycle, age, and efficiency.
How much does it cost to run a 1500 watt heater?
At 0.15 per kWh, a 1500 watt heater costs about 0.225 per hour. Multiply by daily runtime and days used for a monthly estimate.
Does standby power increase electricity costs?
Yes. Standby power is usually small, but always-on devices can add cost over long periods.
Can this calculator estimate monthly appliance cost?
Yes. Enter wattage, hours used per day, electricity rate, number of devices, and days used per month.
Is electricity cost calculated before taxes and fees?
Yes. This calculator estimates energy usage cost from kWh and rate. Utility bills may include extra charges not included here.
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